Typically, teams in any sport say the key to success is being strong through the middle. Yet, in pro football, it's the edge players on defense and the skill players on offense who make the money and the highlights, in large part because of the grunt work done by the interior worker bees.

This year's center class, highlighted by California's Alex Mack, is a deep and talented group. They'll receive playing time, as teams throughout the league need depth at center because so many players currently starting at the position, such as Tennessee's Kevin Mawae and Baltimore's Matt Birk, are getting older.

In last year's draft, the first center was chosen 107th overall -- Cody Wallace of Texas A&M went to the San Francisco 49ers in the fourth round. Kory Lichtensteiger of Bowling Green was taken one pick later by the Denver Broncos. But the strength of this year's group could result in some centers coming off the board earlier this time. While no center is expected to go in the first round, Mack could sneak in late, possibly to the Pittsburgh Steelers with the last pick at No. 32.

Analysis: One of the toughest players at any position in the draft, Mack handles his business out of the traditional under-the-center snap and out of the shotgun. He's a menacing run blocker who is a mauler if he can lock onto a defender. Mack also is a solid pass blocker. His strongest asset is his ability to diagnose defenses and make the needed line calls.

NFL landing spot: The Steelers could nab Mack with the final pick of the first round, but plenty of other teams could try him at guard or move one of their current centers to guard.

Analysis: Besides starting 51 consecutive games, Unger played at left tackle and center, positions that require a variety of different skills. While Unger is not viewed as a tackle in the NFL, his versatility will make him very attractive to a lot of teams that need immediate help or depth. He is accustomed to playing mostly out of a shotgun system and could be best suited for a zone-blocking offense.

NFL landing spot: The Minnesota Vikings need a shot of youth at center after losing Matt Birk to free agency. The Titans could say the same as Mawae turned 38 this offseason.

Analysis: Like Mack and Unger, Wood is tall for this position, but he is tough and durable. He also is excellent in the running game and can mix it up with a 3-4 nose tackle or a 4-3, one-gap defensive tackle. Wood is viewed by some teams as the second-best center behind Mack, and his experience and knack for playing through the whistle will make him very attractive.

NFL landing spot:Atlanta Falcons center Todd McClure is 32 years old, and Wood could transition into the starting role after initially developing as a reserve.

Analysis: Caldwell is a highly accomplished player who started his college career as a guard. His experience going against stout defensive tackles in the SEC has him ahead of the curve. Caldwell is a monster if he gets his hands on players and is considered a strong drive blocker. He isn't great at pulling, so he could be a good fit for teams that don't use a lot of interior movement with their linemen.

NFL landing spot: Teams that face 3-4 fronts might want to grab Caldwell since he can hold his own against massive, brute-force nose tackles.

Analysis: A former nose tackle, Shipley is a scrapper who loves to mix things up. He won the Rimington Trophy, awarded to college football's most outstanding center, and the fact that he projects behind a handful of other prospects shows the depth of talent in this center class. Shipley's strengths project that he could be a good fit for a zone-blocking team, although he also is rough enough to play in drive-blocking sets.

NFL landing spot: The Houston Texans and Titans probably would like to nab a talent like this in the middle of the draft.